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This article mainly shows you "what is the use of the mapfile command in Linux", the content is easy to understand, clear, hope to help you solve your doubts, the following let the editor lead you to study and learn "what is the use of mapfile command in Linux" this article.

Linux common commands mapfile commands mainly read lines from standard input or file descriptors and assign values to arrays.

Mapfile reads rows from standard input and assigns values to the array.

Summary mapfile [- d delim] [- n count] [- O origin] [- s count] [- t] [- u fd] [- C callback] [- c quantum] [array] option-d delim sets delim to the line delimiter instead of the default newline character. -n count gets the most count lines from standard input, and all if count is zero. -O origin is assigned from the location where the array subscript is origin, and the default subscript is 0. -s count skips reading of previous count rows. The line delimiter delim (default is newline character) is removed when-t reads. -u fd is read from the file descriptor fd. -C callback calls the callback statement whenever a quantum row is read. -c quantum sets the number of rows read to quantum. If you do not specify the value of quantum with-c when using-C, then quantum defaults to 5000. When the callback statement is executed, the next subscript to be assigned to the array and the row read are passed to the callback statement as additional parameters. If no starting position is provided when using-O, mapfile clears the array before the actual assignment. Parameter array (optional): the name of the array used for output. If no array name is specified, it is written to the array with the variable name MAPFILE by default.

The return value returns success unless an illegal option is used, the specified array is read-only, and the specified array is not a subscript array.

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